Study On The Simulation Of The Paddy Pot Seedling Movementand The Improvement Of Automatically Feed-tray Device

China is the largest rice producing country,but the level of rice production mechanization in China is relatively low.At this stage,there are various kinds of rice planting machine in China,and throwing transplanter is one of them.The study on the rice transplanting mechanization is mainly focused on the effect of transplant.But it is generally time-consuming and labour-consuming to do the soil-tank experiments or to do the field experiments.At the same time,it is necessary to feed the trays by hand using the rice transplanter.These lead to lower overall labor efficiency.For these reasons,this paper studies from the simulation of the movement of paddy pot seedlings and the improvement of the automatically feed-tray devices.1.Simulated the movement of paddy pot seedlings in the whole process of throwing transplantation by combining ANSYS/FLUENT and ANSYS/LS-DYNA,and used the high-speed photography experiment to verify the simulation.The simulation included 2 parts.The first part is simulating the gas velocity in the five-pipe model with the ANSYS/FLUENT to get the gas velocity at the nozzle outlet.The second part is simulating the movement of the paddy seedlings in the outer guiding tubes and inner guiding tubes.ALE algorithm was used in the simulation of the movement of the paddy seedlings.And the initial data of the air velocity at the outlet of the nozzles was given from the result of the FLUENT simulation.The results show that the lateral position of the paddy seedlings would be concentrated when they were thrown out the guiding tubes.And there is no obvious rule in the distribution of the longitudinal position of the paddy seedlings.The movement time of the seedlings in the inner tubes is less than the time in the outer tubes.The time difference is 0.075-0.101 s.The vertical velocities of the seedlings at the outlet of the inner tubes are 2.93-3.43m/s,and the same velocities at the outlet of the outer tubes are 2.70-3.01m/s.The paper gained each data of the paddy seedlings at the outlet of the guiding tubes from the high-speed photography experiment.It included the position distributions of the seedlings,the vertical velocities of the seedlings and the movement time difference between the motion of the seedlings in the inner tubes and the outer tubes.The results of the highspeed photography experiment verified the rationality of the simulation model.It is proved that the simulation experiment can be used to replace the soil-tank experiment and field experiment.2.Some solutions were carried out to solve the problem of unreliable automatically feed-tray process.It included determining the angle between each fixed column of tray on the transplanting roller,determining the angle and position when feeding the tray,and using the new sensing mode.The angle between each fixed column of tray on the transplanting roller should be 12°.When determining the angle and position when feed the tray,it was achieved through the improvement of the upper part of the guiding tubes and the addition of the transition support plate.The angle ? is determined to be 30°,and the angle ? is determined to be 12°.These were determined by the experiment.Finally,it used the series connection of the diffuse reflection photoelectric sensors to replace the original sensing mode.3.The modal analysis of the key parts of the automatically feed-tray device was carried out to avoid the resonance.The results of the simulation show that the improved guiding tubes and the transition support plate can meet the design requirements.The results also show that the support structure of the convey-tray mechanism may resonate with the frequency of the main vibration source of the transplanter.After changing the fixed mode to symmetrical distribution and changing the diameter of the circular shaft to 10 mm,the support structure of the convey-tray mechanism can avoid the resonance.